What's the removal rate of Ca++ ?

After an action potential, the intracellular Ca++ concentration may rise to
1000 nM, while the resting intracellular [Ca++] is only on the order of
100nM. The removal rate of [Ca++] appears to be crutial to burstors or cell
firing toniclly.
But I don't know what the removal rate of [Ca++]... :(
please help